Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
  • C09K8/02—Well-drilling compositions
  • C09K8/04—Aqueous well-drilling compositions
  • C09K8/14—Clay-containing compositions
  • C09K8/18—Clay-containing compositions characterised by the organic compounds
  • C09K8/20—Natural organic compounds or derivatives thereof, e.g. polysaccharides or lignin derivatives
  • C09K8/206—Derivatives of other natural products, e.g. cellulose, starch, sugars

Definitions

• the invention relates to the use of carboxymethyl and sulfoethyl group-containing cellulose derivatives (CMSEC) in drilling fluids.
• CMSEC carboxymethyl and sulfoethyl group-containing cellulose derivatives
• polymers are used in water-based drilling fluids to adjust the viscosity and to reduce water loss. This prevents the drilling fluid from flowing into permeable formation areas during the drilling process.
• a suitable rheology of the drilling fluid ensures that the drilled rock is optimally discharged from the borehole.
• the polymers used are said to maintain viscosity and water binding in the presence of electrolytes, primarily alkali and alkaline earth salts, under the temperature conditions prevailing in the borehole.
• CMC carboxymethyl celluloses
• starch derivatives starch derivatives
• synthetic polymers GV Chilingarian, P. Vorabutr: Developments in Petroleum Sci. 11, Elsevier Scientific Publishing Company, Amsterdam, 1981, Drilling and Drilling Fluids.
• Synthetic products based on acrylic acids, acrylamides and their copolymers have the major disadvantage that they only have a lower salt stability, especially towards polyvalent ions.
• Synthetic polymers, which also have a high stability towards polyvalent ions, such as calcium and magnesium, are very expensive, so that their use is often out of the question for economic reasons.
• Starch derivatives have an increased stability towards multivalent ions, such as calcium and magnesium, but they have a lower temperature stability. It is known that starch or starch derivatives lose a great deal of their effectiveness in a temperature range from 100 to 120 ° C. and thus become unusable.
• the carboxymethyl celluloses (CMC) known from US-A-2 425 768 have very good properties for reducing water loss in water-based drilling fluids, but have a limited stability towards polyvalent ions, such as calcium and magnesium.
• the production of pure sulfoethyl cellulose (SEC) has been described in US-A-2 132 181.
• the sulfoethyl celluloses known from US-A-4,519,923 have the disadvantage that the pure sulfoethyl celluloses are very expensive.
• CMSEC carboxymethylsulfoethyl cellulose
• the object of the present invention was to develop electrolyte and temperature stable polymers for improved drilling fluids. These polymers should also be usable in highly saline rinsing systems in the presence of polyvalent cations and at temperatures up to 160 ° C. from an economic point of view.
• the cellulose derivatives to be used according to the invention have a significantly improved stability towards polyvalent ions, e.g. Calcium and magnesium.
• the good temperature stability of the carboxymethyl celluloses is also present in the products according to the invention.
• the viscosity of the cellulose derivatives to be used according to the invention to be used depends on the requirements of the rinsing system.
• Low-viscosity cellulose derivatives are used to adjust a water loss of less than 10 ml (according to API standard) or at elevated temperatures (140 to 160 ° C).
• low-viscosity cellulose derivatives are understood to be those which in 2% strength by weight aqueous solution at 20 ° C. have a viscosity of ⁇ 1000 mPa.s at a shear rate of Have 2.5 sec ⁇ 1.
• the concentration of such cellulose derivatives is preferably from 0.5 to 4, in particular from 1 to 3,% by weight, based on the amount of water present in the drilling fluid.
• Highly viscous cellulose ethers are used due to their higher yield, especially at lower temperatures and to achieve a water loss of ⁇ 15 ml according to the API standard.
• highly viscous cellulose derivatives are understood to be those which have a viscosity of> 1000 mPa.s in 2% by weight aqueous solution at 20 ° C. and a shear rate of 2.5 sec 2,51.
• Such compounds are preferably used in amounts of 0.1 to 2, in particular from 0.5 to 1.5, based on the amount of water present in the drilling fluid.
• the cellulose derivatives used according to the invention lead to drilling muds which show excellent properties even in the presence of polyvalent ions (such as calcium2+, magnesium2+) at elevated temperatures (140 to 160 ° C).
• polyvalent ions such as calcium2+, magnesium2+
• the products according to the invention can thus be used in all water-based liquids which are used for sinking and treating boreholes and deep boreholes, in particular in liquids which ensure the borehole stability during the borehole treatment, and in liquids which serve the purpose to improve the flow paths for crude oil and natural gas (fractions) by pressing in under high pressure.
• the composition of these liquids can be completely different from that specified in the examples.
• the compounds to be used according to the invention can preferably be prepared by the slurry process, it being possible, for example, to use as slurry medium: primary, secondary or tertiary alcohols, such as methanol, ethanol, isopropanol, tertiary butanol or a mixture thereof.
• slurry medium primary, secondary or tertiary alcohols, such as methanol, ethanol, isopropanol, tertiary butanol or a mixture thereof.
• Other water-miscible organic solvents such as acetone
• pulp other than those mentioned can also be used.
• the viscosity level of the products can be adjusted as required by known methods by reducing or increasing the temperature or by adding air, H2O2 or other oxidizing substances during or before the alkalization.
• the reaction time and temperature can be changed during manufacture.
• the products obtained after washing are practically free of low molecular weight contaminants. After air drying, the products still contain residual moisture.
• drilling fluids are measured and assessed in accordance with the internationally recognized standards of the American Petroleum Institute (Standard Procedure for Testing Drilling Fluids, API RP 13 B, Sixth Edition, April 1976, issued by American Petroleum Institute, Production Department, 300 Carrigan Tower Building, Dallas, Texas 75201, USA).
• Table 1a The exact composition of the drilling fluid in mixed salt systems using low-viscosity cellulose ethers according to the invention, referred to in the table as an additive, can be found in Table 1a.
• the drilling fluids were subjected to a series of sequential loads in the roller furnace. The samples are aged for 15 hours at room temperature, then for 15 hours at 80 ° C and finally for 15 hours at 140 ° C.
• Table 1b shows the rheological data obtained after the final aging at 140 ° C and the water loss. As can be seen from Table 1b, the examples according to the invention show very good values for the water loss in the flushing system used after aging.
• a commercially available low-viscosity carboxymethyl cellulose (CMC) is listed in Table 1b.
• Table 2a shows the exact composition of the drilling fluid when using high-viscosity cellulose ethers.
• the amount of highly viscous cellulose ethers used (referred to in the table as an additive) is 1%.
• the samples were at room temperature and 15 hours then aged at 80 ° C for 15 hours.
• Table 2b shows the data measured after aging at 80 ° C.
• Examples 12 and 13 show significantly lower water losses with good rheological properties compared to a commercially available, highly viscous CMC which represents the prior art.
• SWDC salt water drilling clay
• Table 3 shows the production conditions of Examples 1 to 13. Examples 2-13 were produced analogously to example 1. In some examples, some of the isopropanol was replaced by methanol.
• Examples 12 and 13 were carried out analogously to Example 1.
• the spruce sulfite pulp was replaced by cotton linters.

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• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Polysaccharides And Polysaccharide Derivatives (AREA)
• Detergent Compositions (AREA)
• Paper (AREA)

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• 1987
  • 1987-12-11 DE DE19873742105 patent/DE3742105A1/de not_active Withdrawn
• 1988
  • 1988-11-23 NO NO885210A patent/NO175645C/no unknown
  • 1988-12-03 EP EP88120201A patent/EP0319868B1/de not_active Revoked
  • 1988-12-03 DE DE8888120201T patent/DE3878858D1/de not_active Revoked
  • 1988-12-09 US US07/282,166 patent/US4972007A/en not_active Expired - Fee Related

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